Efficient Utilization of Echocardiography
Background: We hypothesized that patients could be selected for echocardiographic evaluation of left ventricular (LV) systolic function on the basis of historic, clinical, radiographic, and electrocardiographic criteria.
Methods and Results: We prospectively evaluated 300 consecutive inpatients referred for the echocardiographic assessment of LV function, of whom 124 (41%) had LV systolic dysfunction (LVSD) (LV ejection fraction <0.45). Among the historic variables, male sex was the only predictor of LVSD, whereas of the abnormal physical and radiographic findings, cardiomegaly on chest radiography was the only predictor. Among the electrocardiographic findings, the presence of left bundle branch block was positively correlated with the presence of LVSD, whereas a normal electrocardiogram was negatively correlated with this finding. Only 2 patients with LVSD had a normal electrocardiogram. The addition of significant predictors on physical examination and chest radiography doubled the predictive value of the historic variables for determining LVSD. The addition of electrocardiographic findings further doubled the predictive value of the model. Almost 45% of the predictive power of the final multivariate model (chi-square of 48 of the total chi-square of 108) was based on the absence of normal electrocardiogram in patients with LVSD. When chest radiographic findings were excluded from the model, the overall predictive power of the model did not change, with the normal electrocardiogram gaining greater prominence: Full 56% of the predictive power of the model (chi-square of 60 of the total chi-square of 108) resided in the ability of a normal electrocardiogram to discriminate between patients with and those without LVSD.
Conclusions:Historic, chest radiographic, and electrocardiographic variables can be used to predict low likelihood of LVSD on echocardiography. In particular, when the electrocardiogram is normal, it is extremely unlikely to have LVSD. It can be argued that such patients should not be referred for echocardiography.
Unnecessary tests and procedures account for about one sixth of the $1 trillion health care cost in the United States. One of the fastest-growing tests in health care, and definitely the fastest-growing in cardiology, is echocardiography. It is estimated that more than 15 million echocardiograms were performed in the United States in 1997 alone. One of the most common indications for echocardiography is the assessment of left ventricular (LV) systolic function, which accounts for approximately one third of the echocardiograms ordered at our institution. Physicians of all backgrounds and in all clinical contexts request the test.
We hypothesized that patients could be selected for echocardiographic evaluation of LV systolic function on the basis of historic, clinical, radiographic, and electrocardiographic criteria. To test this hypothesis, we performed a prospective study of inpatients referred to our echocardiography laboratory for the evaluation of LV systolic function.
Background: We hypothesized that patients could be selected for echocardiographic evaluation of left ventricular (LV) systolic function on the basis of historic, clinical, radiographic, and electrocardiographic criteria.
Methods and Results: We prospectively evaluated 300 consecutive inpatients referred for the echocardiographic assessment of LV function, of whom 124 (41%) had LV systolic dysfunction (LVSD) (LV ejection fraction <0.45). Among the historic variables, male sex was the only predictor of LVSD, whereas of the abnormal physical and radiographic findings, cardiomegaly on chest radiography was the only predictor. Among the electrocardiographic findings, the presence of left bundle branch block was positively correlated with the presence of LVSD, whereas a normal electrocardiogram was negatively correlated with this finding. Only 2 patients with LVSD had a normal electrocardiogram. The addition of significant predictors on physical examination and chest radiography doubled the predictive value of the historic variables for determining LVSD. The addition of electrocardiographic findings further doubled the predictive value of the model. Almost 45% of the predictive power of the final multivariate model (chi-square of 48 of the total chi-square of 108) was based on the absence of normal electrocardiogram in patients with LVSD. When chest radiographic findings were excluded from the model, the overall predictive power of the model did not change, with the normal electrocardiogram gaining greater prominence: Full 56% of the predictive power of the model (chi-square of 60 of the total chi-square of 108) resided in the ability of a normal electrocardiogram to discriminate between patients with and those without LVSD.
Conclusions:Historic, chest radiographic, and electrocardiographic variables can be used to predict low likelihood of LVSD on echocardiography. In particular, when the electrocardiogram is normal, it is extremely unlikely to have LVSD. It can be argued that such patients should not be referred for echocardiography.
Unnecessary tests and procedures account for about one sixth of the $1 trillion health care cost in the United States. One of the fastest-growing tests in health care, and definitely the fastest-growing in cardiology, is echocardiography. It is estimated that more than 15 million echocardiograms were performed in the United States in 1997 alone. One of the most common indications for echocardiography is the assessment of left ventricular (LV) systolic function, which accounts for approximately one third of the echocardiograms ordered at our institution. Physicians of all backgrounds and in all clinical contexts request the test.
We hypothesized that patients could be selected for echocardiographic evaluation of LV systolic function on the basis of historic, clinical, radiographic, and electrocardiographic criteria. To test this hypothesis, we performed a prospective study of inpatients referred to our echocardiography laboratory for the evaluation of LV systolic function.